/*
 * Wslay - The WebSocket Library
 *
 * Copyright (c) 2011, 2012 Tatsuhiro Tsujikawa
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#include "wslay_stack.h"

#include <string.h>
#include <assert.h>

struct wslay_stack *wslay_stack_new()
{
    struct wslay_stack *stack = (struct wslay_stack *)malloc(sizeof(struct wslay_stack));
    if (!stack) {
        return NULL;
    }
    stack->top = NULL;
    return stack;
}

void wslay_stack_free(struct wslay_stack *stack)
{
    struct wslay_stack_cell *p;
    if (!stack) {
        return;
    }
    p = stack->top;
    while (p) {
        struct wslay_stack_cell *next = p->next;
        free(p);
        p = next;
    }
    free(stack);
}

int wslay_stack_push(struct wslay_stack *stack, void *data)
{
    struct wslay_stack_cell *new_cell = (struct wslay_stack_cell *)malloc(sizeof(struct wslay_stack_cell));
    if (!new_cell) {
        return WSLAY_ERR_NOMEM;
    }
    new_cell->data = data;
    new_cell->next = stack->top;
    stack->top     = new_cell;
    return 0;
}

void wslay_stack_pop(struct wslay_stack *stack)
{
    struct wslay_stack_cell *top = stack->top;
    assert(top);
    stack->top = top->next;
    free(top);
}

void *wslay_stack_top(struct wslay_stack *stack)
{
    assert(stack->top);
    return stack->top->data;
}

int wslay_stack_empty(struct wslay_stack *stack)
{
    return stack->top == NULL;
}
